I've manged to Kill 3 differnt turbo's on my Diesel Dodge. All happened at high boost levels > 40 PSI. It's best to operate you turbo witin the compressor map. If you get to close or outside of the edge of the map the compressor enters the realm of stall or surge. Also a blowoff valve is a real good idea if you are running a lot of boost.

If you keep the boost at sane levels and allow the turbo to cool down at idle after some hard running a turbo will last many many thosands of miles.